Mammal hair or fur grows in cycles and goes through three phases: anagen, catagen and telogen. In the anagen phase, hair is actively and continuously growing. Afterwards, hair goes through a short period of growth recess (catagen) and enters into telogen in which hair stops growing. The control of the hair growth cycle in mammals is poorly understood. Under normal conditions, it is predominantly controlled by photoperiod. For example, dogs and cats in northern United States shed mainly in spring and fall. Other factors such as genetics, nutrition, and hormones may also affect hair growth cycle.
Alopecia is an abnormal condition in mammals. It is defined as an absence of hair from areas of skin where hair normally is present. It could be due to loss of hair follicles or an abnormally extended telogen period after alopecia in the affected area. In the case of canine and feline, some alopecia are congenital and hereditary while others are caused by various abnormal conditions. The former can be seen in canine color mutant alopecia, feline alopecia universalis, pattern baldness of dachshund, etc. and the latter are generally called acquired alopecias such as canine and feline pinal alopecia, preauricular feline alopecia, anagen telogen defluxion, feline symmetric alopecia, and post-clipping alopecia.
Post-clipping alopecia is commonly seen in veterinary practice. Post-clipping alopecia can last for as long as 6 to 12 months after initial hair clipping. From time to time hair has to be removed or clipped, for example, prior to an operation the canine will be clipped along the area of incision so as to provide a clear field for the surgeon. Treatment of a skin condition oftentimes requires the clipping of hair around the affected area. Other occasions of clipping include venipuncture for drawing blood or injecting medicine. In each of these situations there is a need to have hair growth occur in a rapid and nonselective manner. This will provide a smoothly integrated coat in as short a time as possible.
It has now been found that hair growth can be rapidly accelerated through the application of an alcoholic composition to the surface of the dog""s skin. This appears to bring about a more rapid passage of hair growth from the telogenic stage to the anagenic stage or stimulating hair growth rate or both.
In accordance with the invention there is a liquid composition comprising an alcohol or mixture thereof in sufficient quantity to grow hair in an area of a canine or feline skin wherein alopecia has occurred.
Another aspect of the invention is a method for growing hair on the skin of a canine or feline following alopecia which comprises applying to the skin of the said dog the composition of the invention in quantities and frequency sufficient to grow hair following the said alopecia.
The alcohol(s) can be applied to the skin directly, or through contacting the skin with materials having absorbed alcohol such as cotton, gauze, sponge and cloth or through a vehicle used to deliver the alcohols to the skin surface. The vehicle is any liquid that solubilizes or emulsifies the alcohol(s), is easily spreadable on the skin and provides enough absorption of the alcohol(s) so as to provide the hair growing effect.
The alcohols can be used alone or in mixtures, applying directly to the canine or feline skin together with a vehicle or contacting material as mentioned previously. Such alcohol includes mono or polyalcohols such as methanol, ethanol, isopropanol, propanol, butanol, ethylene glycol, propylene glycol, glycerin, polyethylene glycol, polypropylene glycols, ethylhexane diol, hexylene glycols, and the like, a blend of ethylalcohol with varying amounts of other water soluble alcohols, particularly methanol and isopropanol, or a mixture of methanol and isopropanol. Generally ethanol is a major portion by volume. A particularly desirable group of alcohols is ethanol with methanol and/or isopropanol. Generally about 75 to about 98 vol. % ethanol with the remainder being methanol and/or isopropanol is particularly desirable with about 80 to about 94 vol. % ethanol and about 6 to about 20 vol. % methanol and/or isopropanol, preferably the mixture of methanol and isopropanol being even more desirable. Quantities of specific alcohol(s) employed as well as frequency of use is dependent upon toxicity to the animal.
The quantity of alcohol(s) applied to the skin surface is that quantity of alcohol(s) which bring about a more rapid hair growth in comparison to non-treated skin. Generally, the treated skin should be fully covered with the alcohol or the alcohol mixture for a sufficient length of time, e.g., about 2 minutes. Removal of stratum corneum using materials such as D-Square sampling disc in the treated area before alcohol treatment can facilitate the penetration of the alcohol into the skin. The frequency of application can be once or twice every two to four weeks for up to six to nine months. The alcoholic treated skin appears to take hair from the telogenic stage of essentially nongrowth to the anagenic stage of growth or brings about more rapid hair growth.
A further use of the invention is as an animal model for studying the regulation of hair growth cycle in mammals through bringing hair growth into different growth phases, i.e., anagen, catagen or telogen, in a controlled manner.